The user may, in some circumstances, and particularly during a long journey, lose his bearings and have difficulty telling whether his timepiece is displaying the daytime or night-time, or even the morning or afternoon, hereinafter respectively designated “AM” and “PM”. Hereinafter a visual display showing the time of day in relation to the midday hour will be called an “AM/PM” display.
Numerous devices are known for solving the first problem of the day-night display, generally based on a disc, connected to a twenty-four hour wheel of the timepiece, a coloured part of which is visible through an aperture, with distinct colours for the day and night. CH Patent Application No 671 317 A3 in the name of GASTON GAGNEBIN is also known, disclosing a timepiece wherein daytime and night-time are represented by images of the sun and a star carried by an indicator disc and appearing alternately in an aperture. U.S. Pat. No. 6,359,839 B1 in the name of SCHENK THOMAS is also known, with a specific display for the same purpose showing transitory periods.
The problem still remains unresolved for the transitory phases of dawn and dusk, for which the user has no information enabling him to differentiate between them, to know where he is in relation to midday.